Sealey mighty mig 150

[sean logieParticipant @seanlogie69385]

Has anyone replace the liner in one of these ? I know how just not sure of which one . The one I took out of my welder was in 2 pieces which doesn't seem right to me . From where the liner enters the gun for about 1/2" in ,from there there was a another piece of liner the length of the gun up to the nozzle . Is this right or not . I've been a stick welder up to now ,so I'm not up speed on the mig welder and it's in's and outs . I would've thought it would need to be one continuous piece .

Sean

[sean logieParticipant @seanlogie69385]

Liner

[HacksawParticipant @hacksaw]

I have one . Yes , mine is a separate piece , which is a right pain, as when loading a new wire ,invariably means taking the gun apart , as it never finds the hole in the tubing . Since it's on the bend in the nozzle it eventually wears through too..from the friction of the moving wire , and then the shroud goes live too !! Any old plastic tube kicking around that's the right bore seems to work as a replacement ok …like a bit of airbrush airline ..( cowbow , i am  )

Edited By Hacksaw on 31/03/2018 15:42:24

[HacksawParticipant @hacksaw]

Those red tubes that come with WD40 ..a bit of that works too on 0 .6 wire in an emergency ..

So i've heard…

[sean logieParticipant @seanlogie69385]

Which flux core do you chaps suggest .

Sean

[HacksawParticipant @hacksaw]

Gasless wire ? Never tried it . Don't you have to reverse the gun polarity with that stuff ? I've only ever used CO2 or Hobbyweld 5 gas

[Neil WyattModerator @neilwyatt]

Posted by sean logie on 31/03/2018 16:03:19:

Which flux core do you chaps suggest .

Sean

Depends what you are welding!

[sean logieParticipant @seanlogie69385]

Mainly mild steel .

Sean

[Neil WyattModerator @neilwyatt]

Bog standard flux-cored mild steel wire then

[sean logieParticipant @seanlogie69385]

Now I don't know much about electronics,so I'll try and explain . The relay that powers the the wire feed kinda pleases it's self when it works lol . I noticed yesterday there was a hole in the side of the plastic cover ,I also noticed it was sparking and flashing when I pulled the trigger on the gun .Then when it didn't work it was clicking ,now I think even I know that's not how a relay should behave .

 

Here's the culprit

To replace the relay ,is it  a case of touching the connectors on the back of the PCB with the hot soldering iron  .I'm a little concerned about damaging the PCB in doing this . Any tips ?

Edited By sean logie on 15/04/2018 07:39:48

[Gray62Participant @gray62]

Ideally you need to remove as much solder as possible from each of the pads before trying to remove the relay from the board. Get yourself some solder wick. The wick will take up most of the solder and will also sink some of the heat so reducing the risk of damaging the pads on the board. Don't keep the iron on each pad too long, of all the solder is not removed, let the pad cool and do another one, then go back around. Too much heat in one go will risk lifting the pad and burning the pcb.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Sean, get yourself some de-soldering braid. If your hurry to a Maplin's shop, you maybe lucky to get some.

**LINK**

Regards Nick.

Graeme beat me to it.

Edited By Nicholas Farr on 15/04/2018 09:01:08

[doubletopParticipant @doubletop]

As the relay is completely stuffed. Take a note of all the markings to help you search for a replacement. Then carefully break off the outer case and using snips cut away as much as the relay as you can. You are trying to get it down to 4 separate connections coming out of the board.

Using pliers grip the connection on the component side and unsolder on the solder side and pull the connection free. Repeat for the other three.

It may seem a bit drastic at first but it is far easier than trying to wrestle out 4 connections at the same time.

Pete

[doubletopParticipant @doubletop]

It looks like it is one of these

 

**LINK**

Data Sheet here

http://www.hongfa.com/pro/pdf/HF102F_en.pdf

Beware when searching Ebay. You want a 24v version and they all seem to be selling the 12V version which appears to be JQX 102F. However some are advertising the HF 102F but as 12v which you don't want.

Pete

Edited By Doubletop on 15/04/2018 09:28:33

Edited By Doubletop on 15/04/2018 09:49:53

[sean logieParticipant @seanlogie69385]

Posted by Doubletop on 15/04/2018 09:24:02:

As the relay is completely stuffed. Take a note of all the markings to help you search for a replacement. Then carefully break off the outer case and using snips cut away as much as the relay as you can. You are trying to get it down to 4 separate connections coming out of the board.

Using pliers grip the connection on the component side and unsolder on the solder side and pull the connection free. Repeat for the other three.

It may seem a bit drastic at first but it is far easier than trying to wrestle out 4 connections at the same time.

Pete

This was my plan Pete ,thanks

Sean

[sean logieParticipant @seanlogie69385]

Posted by Nicholas Farr on 15/04/2018 08:37:41:

Hi Sean, get yourself some de-soldering braid. If your hurry to a Maplin's shop, you maybe lucky to get some.

**LINK**

Regards Nick.

Graeme beat me to it.

Edited By Nicholas Farr on 15/04/2018 09:01:08

All ready ordered

Sean

[sean logieParticipant @seanlogie69385]

Posted by Doubletop on 15/04/2018 09:26:50:

It looks like it is one of these

 

**LINK**

Data Sheet here

**LINK**

Beware when searching Ebay. You want a 24v version and they all seem to be selling the 12V version which appears to be JQX 102F. However some are advertising the HF 102F but as 12v which you don't want.

Pete

Edited By Doubletop on 15/04/2018 09:28:33

Edited By Doubletop on 15/04/2018 09:49:53

Thanks again Pete , I nearly fell foul on the 12v version .Mine is the HF102F 24v 20A 

 

Sean

Edited By sean logie on 15/04/2018 11:47:14

[Anthony DrakeParticipant @anthonydrake63078]

On the subject of gas less wire I have used this type of wire with and without gas on 400 amp machines, I am using machine Marts 0.9mm wire which I have used on car body work on a 100 amp mig which is good wire compared to the industrial wire I have used.

Regards Tony

[SillyOldDufferModerator @sillyoldduffer]

Anyone got a theory as to why Sean's relay should fail like that? My first thought was that there's a dud capacitor across the contacts but the symptoms don't match. Could it be physical damage, something whacked into the case in the past?

I prefer a desoldering pump to wick; both are useful depending on the job.

Dave

[doubletopParticipant @doubletop]

Posted by SillyOldDuffer on 16/04/2018 09:37:17:

Anyone got a theory as to why Sean's relay should fail like that? My first thought was that there's a dud capacitor across the contacts but the symptoms don't match. Could it be physical damage, something whacked into the case in the past?

I prefer a desoldering pump to wick; both are useful depending on the job.

Dave

Here is the parts list with the circuit diagram **LINK**

The only thing the relay does is switch the power transformer, maybe the back emf of a lot of repeated heavy current welding (switch setting on MAX 1)  has finally killed the relay. Just a case of component mortality?

Pete

Edited By Doubletop on 16/04/2018 12:15:39

[sean logieParticipant @seanlogie69385]

The link for the welder is different setup to mine unfortunately.

Sean

[doubletopParticipant @doubletop]

Posted by sean logie on 16/04/2018 16:23:18:
The link for the welder is different setup to mine unfortunately.

Sean

Sean

Maybe but the overall principles of the design will be similar. Here is another link with various posts of circuit diagrams for MightyMig variants

**LINK**

Maybe different models but in all the cases the relay switches on the primary to the transformer. The variation is the way the voltage control taps on the transformer are selected.

One other thought is the state of the transformer and whether you've got a short between the coils and it is overloading the relay. Give it a visual check to see if there is any obvious arcing. There was a time I could do the maths on transformers and possibly advise a method of checking with a meter. Unfortunately those days are long gone.

Otherwise I'd suggest you jump on the mig welding forum in the link I've given you and ask the same question there.

Pete

[doubletopParticipant @doubletop]

Or

**LINK**

Pete

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